indices

问题 This question comes as a companion of this one that regarded fastest sorting of a double array. Now I want to get the top- k indices corresponding to the unsorted array. I have implemented this version which (unfortunately) uses autoboxing and HashMap as proposed in some answers including this one: HashMap<Double, Integer> map = new HashMap<Double, Integer>(); for(int i = 0; i < numClusters; i++) { map.put(scores[i], i); } Arrays.sort(scores); HashSet<Integer> topPossibleClusters = new

问题 I need help solving an indexing problem. The assigned problem states: Two matrices (x and y) give the coordinates to form matrix B from matrix A. Produce the matrix B which contains the values of A at the given coordinates in x and y. For instance: x = [1 1 1; 2 2 1] y = [1 2 1; 3 2 4] %This would read as (1,1),(1,2),(1,1),(2,3),(2,2),(1,4) % Given matrix: A = [6 7 8 9; 10 11 12 13]; %This would give us this answer for B (using the coordinate scheme above): B=[6 7 6; 12 11 9]; I'm guessing I

问题 I am trying to select amounts from an array given a criteria and reject the other amounts that do not fit. The criteria is: if amount[i,:]> x*amount[i-1,:] keep, otherwise keep prior amount. just like a treshold basically. And I am filling all these amount selected within a new array Array1. In the end the curve array takes it all and draws a curve. Now, the curve somehow always give me the same curve no matter what treshold i put in. This leads me to think that something is wrong with my

问题 I'm trying to load simple 3d model cube.3ds, but next error occurs: when I read indices to my vector, vector contains: [0, 1, 2, 3, ...]. It's not properly. I found almost the same topic: Assimp and D3D model loading: Mesh not being displayed in D3D, but I don't found the answer. Can anyone describe in detail properly algorithm for loading indices from meshes. Thank's a lot! 回答1: Here is a example pulled from the assimp sample code on accessing the mesh indices. for (; n < nd->mNumMeshes; ++n

问题 This question already has answers here : Finding all positions of substring in a larger string in C# (12 answers) Closed 6 years ago . EDIT: So it turns out what I had before was correct, I was simply counting the indexes wrong. Thank you for your input though. Working on a method that finds all substring indices in a given string from the user. I am having issues with getting correct positions from userString.IndexOf. I know it's finding all occurrences of the substring, but the integer

问题 I have a large dataset that I need to divide randomly into 5 almost equal sized sets for cross validation. I have happily used _crossvalind_ to divide into sets before, however this time I need to divide chunks of data into these groups at a time. Let's say my data looks like this: data = [1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18]; Then I want to divide them randomly into 5 groups in chunks of 2, e.g. like this g1 = [3 4], [11 12] g2 = [9 10] g3 = [1 2], [15 16] g4 = [7 8], [17 18] g5 =

问题 I have input array: np.random.seed(45) a = np.random.randint(100,size=(5,21)) print (a) [[75 30 3 32 95 61 85 35 68 15 65 14 53 57 72 87 46 8 53 12 34] [24 12 17 68 30 56 14 36 31 86 36 57 61 79 17 6 42 11 8 49 77] [75 63 42 54 16 24 95 63 98 22 27 32 16 75 58 60 54 96 70 32 16] [59 92 55 88 5 81 93 79 67 55 60 57 83 27 78 18 87 55 20 9 9] [73 27 57 50 7 57 78 68 23 75 41 39 70 2 71 70 27 47 54 93 19]] Array of indices: b = np.array( [[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [9, 8, 7, 6, 5, 4, 3, 2, 1

问题 This question already has answers here : Pythonic way to return list of every nth item in a larger list (9 answers) Closed 3 years ago . I have a list of 20 items. I want to create a new list than only contains every 5th item of the list. Here is was I have: listA=[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20] for i in len(range(listA)): print i How can I create listB from listA using Python? listB should be equal to [5, 10, 15, 20] . 回答1: You can use this idiom listB = listA[4::5] This

问题 We have a big existing script that drops and recreates tables in (a clone of) our customers database. Our customer might have changed table or index definitions slightly, so our script tries to use the output from dbms_metadata.get_ddl to recreate the tables, but we have problems with function based indices with timestamp expressions. Minimalistic example emulating a customer table: create table t(a timestamp, b timestamp); create index idx_ta on t (nvl(a, TO_DATE('2010-01-02 03:04:05','YYYY

问题 Suppose I have the following data frame in R: set.seed(5) PosActions <- c("Work","Pause","Clockin","Clockout","Lunch") df <- data.frame(ID = c(rep(1,3),rep(2:3,each=4),rep(4,5)), ACTION = sample(PosActions,16,replace=T)) Which returns ID ACTION 1 1 Pause 2 1 Clockout 3 1 Lunch 4 2 Pause 5 2 Work 6 2 Clockout 7 2 Clockin 8 3 Lunch 9 3 Lunch 10 3 Work 11 3 Pause 12 4 Clockin 13 4 Pause 14 4 Clockin 15 4 Pause 16 4 Pause In this data frame, the rows corresponding to ID == 2 and ID == 3 (rows 4